A Non-Orthogonal Multiple Access (NOMA) wireless communication technology is a new wireless access technology proposed in Long Term Evolution (LTE) release 13 of the 3rd Generation Partnership Project (3GPP) research. As shown in FIG. 1, in a NOMA system, data for a plurality of user equipments (UEs) can be multiplexed in each frequency resource block (e.g., a frequency sub-band) to improve throughput of the system, where the data for respective UEs that are multiplexed in each frequency resource block are distinguished by using different powers and successive interference cancellation (SIC) orders; and the SIC order indicates an order in which the data for the respective UEs that are multiplexed in each frequency resource block are demodulated.
In a traditional NOMA system, at a transmitter side (e.g., in a base station), the data for the plurality of UEs to be multiplexed in a frequency resource block are respectively modulated after being encoded to generate modulated signals for the respective UEs, and then the modulated signals for the respective UEs are superposed according to the powers assigned to the respective UEs to generate a composite signal, which is sent to the receiver after various processes (e.g., an inverse fast Fourier transform, an addition of cyclic prefix, and so on). However, when decoding required signals, a UE in a center of a cell needs to firstly detect signals of UEs on an edge of the cell, and then detect signals of its own only after performing interference cancellation on the signals of the UEs on the edge of the cell, which causes a high complexity of the receiver.